uni'wissen 01-2014_ENG

the black grouse. It makes use of forensic molecu- lar biology, a ﬁeld related to forensic medicine: “Instead of looking for a cigarette butt at the scene of a crime we look for feathers, feces, or eggshells. This allows us to create a DNA profile of individual animals.” In order to obtain a com- plete DNA profile from the collected samples, which usually contain only a tiny amount of deoxyribonucleic acid (DNA), the researchers begin by copying the DNA fragments via a poly- merase chain reaction. They then apply electro- phoresis, a method by which the fragments are separated from one another in an electric field. Since the molecules DNA is composed of vary in size and have different electric charges, they move at different speeds in the electric field. The results can then be represented graphically in an electropherogram, which is unique for each individ- ual. In this way, the researchers can characterize the genetic makeup of each individual animal, just as with humans. Genetic Diversity within a Species This method can be used to answer important questions of nature conservation, such as deter- mining the size or migration behavior of a popu- lation. The molecular method is not only an inexpensive and time-saving alternative to the direct observation of animals by means of radio tracking devices but also has the advantage that it can be used on taxidermically prepared animals and archaeological findings. This enabled Segel- bacher to compare current wood grouse samples with historical samples and compile information on the history of the species. For example, he found out there used to be a regular genetic ex- change between wood grouses from the Northern and Southern Black Forest that is now greatly diminished. The case study on dormice shows that popula- tions need to exchange genes with each another in order for the species as a whole to survive. Only with a large amount of genetic diversity do animals remain adaptable, for instance to changing climactic conditions. By comparing the genetic data they have collected with the features of the landscape – such as the forest structure, urban To obtain the DNA profile of a wood grouse, the researchers collect feathers and fecal samples from the ground. Then they use these samples to map the animal’s deoxyribonucleic acid (DNA) in the lab and represent the information graphically in an electropherogram – a genetic fingerprint that looks different for each individual. Photos: Gernot Segelbacher; Montage: Kathrin Jachmann 26